Electrical induction apparatus



Feb. 23, 1932. MATTHEWS 1,846,887

ELECTRICAL INDUCTION APPARATUS Original Filed May 24, 1930 A TTORNEY Patented Feb. 23, 1932 4 UNITED STATES PATENT OFFICE GEORGE A. IA'I'IKEWS, 0F DEIBOIT, MICHIGAN, ASSIGNOR TO Gm ELECTRIC COMPANY, A. CORPORATION OF NEW YORK ELECTRICAL INDUCTION- APPARATUS Application filed Kay 24, 1980, Serial No. 455,214. Renewed December 11, 1931.

The present invention relates to the interference with transmission of sound producing vibrations and while described specifically with respect to liquid filled trans- I formers, is applicable to any liquid filled electrical induction apparatus in which the sound vibration producing element is submer ed or surrounded by liquid.

L1 uid filled transformers, regulators, and

the e, are usually constructed of a suitable unit, such as a magnetic core and a winding or windings, submerged in a body of liquid in a metallic container of comparatively thin walls.

As is well known, in any alternating current induction device, there is usually developed a sound lmown as A. C. hum when the device is operating, and in apparatus of the type indicated, especially in large units, this 'hglm often is so loud as to be quite obj ection- The noise produced by transformers and similar alternating current apparatus probably is caused by radition from vibrating surfaces and its intensity is a function of the frequency and amplitude of this vibration. It is a well known fact that solids and liquids transmit vibrations much better than air or gases and, in the case-of transformers and similar alternating current apparatus, where the device is enclosed and filled with oil or other liquids, the vibrations from the core and windings or other corresponding unit are transmitted by the oil or other liquid to the case or container, causing the latter to vibrate and produce the noise so characteristic of this type of apparatus.

Among the objects of the present invention is to eliminate such noise or at least reduce it to such degree as to be unobjectionable.

' Another object is the provision of a simple and effective means which will reduce or eliminate the hum but which may be added to a' conventional transformer or similar device without in any way interfering with the ratus where similar conditions exist, such as l in voltage regulators, contactors, etc., as above mentioned.

Other objects will readily occur to thoseskilled in the art by reference to the following description and the accompanying drawin in which ig. 1 is a more or less diagrammatic vertical central section through a conventional transformershowing an embodiment of the present invention.

Fig. 2 is a horizontal section on the line 2-2 of Fig. 1.

Fig. 3 is a partial vertical section showing amodified form of construction.

As indicated in the drawings, the transformer includes a container or tank 10, adapted to contain a body of liquid 11 such as a suitable oil, in which is submerged the magnetic core and windings indicated diagrammatically at 12.

There may also be provided the externally arranged circulating cooling pipes 30 of which a few are shown though it should be understood that as many may be-used as will be found desirable.

In the conventional device, vibrations set up in the core 12 are transmitted to the liquid 11, which is always a good transmitter, and impressed upon the container .10, with the result that the more or less resilient wholeproduces quite a loud hum or audible vibration.

In the present invention, the transmittin of the vibration by the liquid is interfere with by surrounding the core unit with a vibration absorbing element 15 indicated supported in any suitable manner in the space between the core unit 12 and the walls of the container and in the preferred form '5 spaced from both, although as indicated in Fig. 3, it may be made aspart of the container itself or even as apart of the core unit.

The preferred form of such elements as indicated, consists of a double walled element 10 15 completely surrounding the transformer within the element 15 and through the openings 17 and descends along the walls of the container 10 and also through the cooling pipes where such pipes are used. The space between the walls of the elements 15 5 and 16 may be exhausted if means is provided to prevent collapse, or air or other sound deadening medium may be used. Any suitable means for supporting these elements in the tank or container may be used. Further, in order to insure the elements 15 and 16 against collapsedue to pressure when the element is constructed with comparatively thin walls, spacing blocks of suitable nonresilient material, such as cork, hard felt, etc. rgraay be used. Such spacers are indicated at As indicated in Fig. 3, instead of providing a separate shield, as'in Figs. 1 and 2, the

shield may be formed integrally with one or 40 the other of the elements 10 and 12, that is, either the transformer or the container 10 or the core unit, or both. In this figure. 'the shield is shown as an integral part of the container which is shown as having a hollow double wall at 150? and a hollow double walled bottom at 16a, the spaced walls being supported by spacers 20 as in Figs. 1 and 2. In apparatus provided with the above de- 0 scribed shield, vibration forces set up by the core unit in the liquid within the shield will not be fixedly transmitted through the latter to the liquid between the shield and the container but absorbed by the shield.

The position and shape of the shield may of course, be changed to conform to the particular design of the apparatus, and such changes are contemplated as being desirable, particularly when the vibration emitting sur- 6 faces,- terminal connections, etc. are arranged in a different or an unconventional manner. Now having described the invention and the ,preferred-embodiment thereof, it is to be understood that the said invention isto be 85 limited, not to the specific details herein set 'forth and illustrated, but only by the scope of the claims'which follow.

I claim 1. Electrical induction apparatus including a magnetic core, a liquid filled container within which the said core is supported, and a vibration absorbing shield completely surrounding the core between the core and the outer wall of the container.

2. Electrical induction apparatus including a liquid holding container, a magnetic core submerged in the liquid within the container, and a vibration absorbing shield within the container and surrounding said core, the liquid within the shield being in communication with that outside the shield to permit circulation of the liquid.

3. Electrical induction apparatus including a liquid holding container, a magnetic core submerged in said liquid within the container, and a vibration absorbing shield submerged in said liquid within the container and surrounding said core, the liquid within the shield bein in communication with that outside the s 'eld to permit circulation of the liquid.

4. Electrical induction apparatus including a liquid'holding conta ner, a magnetic core submerged in the liquid within the container, and means for reducing emission of noise, said means including a ollow walled element surrounding and spaced from said core and from the container, and said element havingopenings to permit circulation of said liquld. i

5. Electrical induction apparatus including a liquid holding container, a magnetic core submerged in said liquid, means for reducing emission of noise, said means including a hollow walled metallic shield submerged in said li aid and surrounding said core, the upper an lower ends of said shield being open to permit circulation of said liquid, and hollow walled disks partially closing the u per and lower openings in said shield, said shield and disks being s aced from said core and from the walls 0 said container. 6. Electrical induction'apparatus including a liquid holding contamer, a magnetic core submerged in said liquid, means for reducing emission of noise, said means including a hollow walled metallic shield submerged in said liquid and surroundin said core, said shield containing a sound a orbin medium, the upper and lower ends of said shield being open to permit circulation of said liquid, and ollow walled disks partiallyclosm theupper and lower openings in said shiel said disks containing a soun absorbing medium, and said shield and disks being s ace'd from said core and from the walls 0 said container.

7. Electrical induction apparatus including a liquid holding container, a magnetic names? core supported in said liquid, and a vibration absorbing shield between said core and the outer wall of said container, said shield completely surrounding the core and having openings to permit circulation of said liqu1d through the shield. a

8. Electrical induction apparatus including a liquid holding container, a magnetifi core supported in said liquid, and a hollow walled vibration absorbin shield containing a sound absorbing medium between said core and the wall of said container, the liquid within the shield being in communication with that outside the shield to permit circulation of the liquid.

GEO. A. MATTHEWS. 

